Although patients with low cerebrospinal fluid (CSF) serotonin metabolite levels have been reported, inborn errors of the rate-limiting enzyme of serotonin synthesis (tryptophan hydroxylase, TPH) have not been described so far. In this study we aimed to evaluate CSF alterations of the serotonin metabolite 5-hydroxyindolacetic acid (5-HIAA) in patients with neurological disorders and to explore a possible TPH deficiency in some of them. A total of 606 patients (286 males, 320 females, mean age 4 years and 6 months, SD 5 years and 7 months) underwent CSF analysis of neurotransmitter metabolites by reverse phase high performance liquid chromatography...

The cholinergic system has been widely implicated in cognitive processes and cholinergic loss is a classical hallmark in Alzheimer disease. Increasing evidence supports a role of the serotonergic system in cognition, possibly through a modulation of cholinergic activity. We compared selective cholinergic denervation by administration of the immunotoxin 192 IgG-saporin in the nucleus basalis of Meynert (NBM) with intracerebroventricular (ICV) lesions of the basal forebrain in male rats 7 days after lesioning...

Effect of p-chlorphenilalanine and 5-hydroxytriptophan on the urine flow (V), glomerular filtration rate (GFR), free water reabsorption (TCH2O), and sodium fraction excretion (ENa.F%) in Wistar rats loaded with water or 2% sodium chloride solution, was studied. It was found that treatment of rats with inhibitor of serotonin biosynthesis, p-chlorphenilalanine (300 mg/kg, 48 hrs before the experiment) had no effect on the kidney response to the water loading in the experimental rats as compared to the control ones: changes in V, GFR, TCH2O and ENa...

Tetrindol, a selective inhibitor of MAOA (predominantly of serotonin oxidase) and fluoxetine, an inhibitor of serotonin neuronal uptake, were studied in psychotropic tests on mice and rats. Both drugs significantly intensified 5-hydroxytriptophan-induced head twitching, reduced the effect of reserpine and the destructive action of maximal electroshock and the scopalamine-induced transient disruption of memory in a test for conditioned response of passive avoidance in rats and mice. In a behavioral swimming test the drugs were less active...

Since 1-(m-chlorophenyl)piperazine (mCPP) is a metabolite of trazodone (TRZ) and etoperidone (ETO), two atypical antidepressants, a pharmacological study was undertaken to establish the possible contribution of mCPP to the effects of the parent compounds. Behavioral effects of mCPP in rats consist in head shakes and other signs of serotoninergic stimulation; subtoxic doses also produce clonic convulsions and prostration. TRZ and ETO produce sedation and signs of alpha-adrenergic blockade; subtoxic doses produce tremors, clonic convulsions and prostration...